The present invention relates to a torsional vibration absorber, and more specifically to a vibration absorber incorporated in a flywheel, clutch disk, or drive shaft system, in particular, in order to absorb torque fluctuation of a combustion engine.
A prior-art absorber of this type comprises a drive plate connected to a drive source, a driven plate connected to a driven member, and resilient means disposed between these two plates, and these two plates are rotated relative to each other by resiliently compressing the resilient means. Particularly, it is well known that the above prior-art absorber is applied to a clutch disk for an automotive vehicle.
The relationship between transmission torque and torsional angle in a power transmission system subjected to influence of the elasticity of various components of an automotive vehicle drive system is roughly linear and has an natural vibration frequency and therefore resonated in a predetermined rotational speed range, thus resulting in undesirable vibrations and noise.
To overcome these problems, conventionally, countermeasures against vibrations and noise have been effected by additionally incorporating a frictional damper invention or by appropriately combining various resilient members of different rigidities to control the torsional torque characteristics in relation to the relative angular displacement between the drive plate and the driven plate according to the degree of the relative angular displacement. For instance, there exists a torsional vibration absorber such that the resilient member is composed of a coil spring and a cushion rubber elastic member disposed in an inner cavity of the coil spring, and a sheet is provided between both ends of the coil spring and both the plates (refer to Japanese Patent Kokai Publication No. 59-200816).